• Journal of Korea Game Society
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• v.20 no.3
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• pp.65-74
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• 2020

In the shadow map method, if the shadow map is magnified, the shadow has a jagged silhouette. Herein, we propose a soft shadow method that filters reshaped silhouettes analytically. First, the shadow silhouette is reshaped through sub-texel edge detection, which is based on linear or quadratic curve models. Second, an integral shadow filtering algorithm is used to accurately obtain the average shadow intensity from a definite integral estimation. The implementation demonstrates that our solution can effectively eliminate jagged aliasing and efficiently generate soft shadows.

• Journal of Korea Game Society
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• v.14 no.2
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• pp.77-84
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• 2014

Presence of soft shadow effects from an area light makes virtual scenes look more realistic. However, since computation of soft shadow effects takes a long time, acceleration methods are required to apply it to real-time 3D applications. Many researches assumed that area lights are white rectangles. We suggest a new method which renders soft shadows under the area light source having arbitrary shape and color. In order to approximate visibility test, we use a shadow mapping result near a pixel. Complexity of shadow near a pixel is used to determine degree of precision of our visibility estimation. Finally, our method can present more realistic soft shadows for the area light that have more general shape and color in real-time.

• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.55-64
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• 2017

In this paper, a novel soft shadow method is suggested to support realistic shadows in mobile ray tracing. In ray tracing, soft shadow is generally generated by sampling a shadow ray. As this sampling method increases the number of rays to be processed, it has undermined the performance. We designed the proposed soft shadow processing method and hardware architecture to overcome this problem through selective shadow generation and triangle address caching for minimizing the performance degradation caused by sampling. The proposed hardware architecture can be integrated into a mobile ray-tracing hardware and was evaluated in terms of its performance on the FPGA. Based on the results, the rendering performance about 4, 8, and 16 samples were improved, respectively, by 40%, 50%, and 56% on average compared to the previous method, and it was found that the real-time soft shadow processing is feasible with the proposed hardware architecture.

• Journal of the Korea Computer Graphics Society
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• v.14 no.1
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• pp.11-16
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• 2008

This paper introduces a novel real-time soft shadowing method applicable for height maps. As well as supporting self-shadowing of the height map, our method allows shadows to be caught on other objects. The method is very suitable for dynamically changing height maps because it requires no precomputation. A shadow height map (SHM) is a new structure which represents the height of the shadow at each discretized coordinate of a height map. Constructing the SHM is O(n), where n is the number of texels in the SHM. Shadow can be computed from this map quickly and simply, using a pixel shader. Examples demonstrate good real-time performance and plausible visual quality.

• Journal of KIISE
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• v.43 no.4
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• pp.399-403
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• 2016

Deferred Shading is a shading technique that postprocesses pixels in the screen space, following geometry-only rendering passes with depth buffering. Unlike typical shadow mapping techniques, this technique allows us to render shadows from multiple light sources without changing the structure of the rendering pipelines. This paper presents a deferred shadow mapping technique and its extension to soft shadows using mipmapping. Our technique first generates visibility maps from light sources, and blurs the visibility maps for deferred shading. This strategy leads to efficient soft-edged shadows, but does not incorporate depth variation, producing light bleeding to some extent. In order to suppress the light-bleeding artifacts, we also propose a depth-adaptive mipmap sampling technique in the screen space.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.11-16
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• 2011

In computer graphics, shadows play a very important role as a hint of inter-object distance as well as themselves in terms of realism. To represent shadows, some traditional methods such as shadow mapping and shadow volume have been frequently used for the purpose. However, the rendering results are not natural since they assume the point light. On the contrary, an area light can render soft-shadows, but its computation is too burdensome due to integral over the whole light source surface. Many alternatives have been introduced, back-projection of occluder onto the light source to get visibility of light or filtering of shadow boundary by calculating size of penumbra. But they also have problems of light bleeding or ringing effects because of low order approximation, or low performance. In this paper, we describe a method to improve those problems using shadow atlas.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.5
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• pp.245-256
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• 2002

Shadows are important elements in producing a realistic image. Generation of exact shapes and positions of shadows is essential in rendering since it provides users with visual cues on the scene. It is also very important to be able to create soft shadows resulted from area light sources since they increase the visual realism drastically. In spite of their importance. the existing shadow generation algorithms still have some problems in producing realistic shadows in real-time. While image-based rendering techniques can often be effective1y applied to real-time shadow generation, such techniques usually demand so large memory space for storing preprocessed shadow maps. An effective compression method can help in reducing memory requirement, only at the additional decoding costs. In this paper, we propose a new image-barred shadow generation method based on image warping. With this method, it is possible to generate realistic shadows using only small sizes of pre-generated shadow maps, and is easy to extend to soft shadow generation. Our method will be efficiently used for generating realistic scenes in many real-time applications such as 3D games and virtual reality systems.

• Journal of the Korean Society of Fashion and Beauty
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• v.5 no.2 s.13
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• pp.31-47
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• 2007

The purpose of this research is to help cosmetic companies to develop new products and make sales strategy by understanding about $20's{\sim}30's$ women's favorite types of eye shadows like as various colors and technique of express. They were divided into groups based on their ages, educational background, careers and monthly income and each group was inquired its preferable cosmetic colors, the time span of the purchase, the motive of the purchase, and the trend of the color cosmetic to analyze the relationship between the trend color and the purchase. It also shows that the most popular color is pink for eye shadow and women have over two colors and cake type ordinary. This survey is showed that women avoid wearing dark or deep colored eye shadow due to natural make-up. Also it showed that women of the times request soft and natural technical makeup for eyes.

• Imaging Science in Dentistry
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• v.32 no.4
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• pp.195-200
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• 2002

Purpose: To evaluate the computed tomographic appearances of post-operative maxillary sinuses. Materials and Methods: 33 asymptomatic cases of post-operative maxillary sinus without evidence of any pathologic changes and clinical symptoms were selected. CT images were classified as opacification, soft tissue shadow, anterior wall depression, naso-antral communication, and compartmentalization. The relationships between the CT image and the age of patients at the time of operatation, and between the CT image and the duration of time elapsed since the surgical procedure were evaluated. Results: The most commonly presented radiological characteristics that occurred after the Caldwell-Luc procedure were opacification and soft tissue shadow. Anterior wall depression and naso-antral communication were radiographic indications that a Caldwell-Luc operation had been carried out. The age of patients when they had been first operated on, and the duration between the surgical procedure and the time of evaluation had no effect on the CT appearances of normal changes. In cases involving a longer time interval between the antral surgery and evaluation, the anterior wall depression with bony healing was more commonly observed than soft tissue healing. Conclusion: The radiographic information regarding the normal healing state using computed tomography can distinguish post-operative changes from inflammatory and cystic disease in patients who have undergone a Caldwell-Luc type of radical maxillary antrostomy.

• Journal of radiological science and technology
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• v.15 no.2
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• pp.11-15
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• 1992

For improving the image quality in case of neck Lateral projections, the Al compensation filter were used and conclusion that, it could be got the high image quality able to observe the shadow of cervical spine, hyoid bone, trachea, soft tissue simultaneously.